Process and apparatus for roasting coffee and other substances.



P. MALVEZIN.

PROCESS AND APPARATUS FOR ROASTING COFFEE AND OTHER SUBSTANCES.

APPLICATION FILED JUNE 12. 19l5 1L $3? @3 1 w Patented Aug. 21, 1917.

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PROCESS APPARATUS FOR ROASTING CQFFEE AND OTHER, SUBSTANCES.

Specification of Letters Patent. Patented Aug, 21, T9917.

Application filed June 12, 1915. Serial No. 33,763.

To all whom it may concern:

Be it known that I, PIERRE MALVEZIN, a citizen of the French Republic,and residing in Sceaux, (Seine), France, 7 Rue Quesney,

engineer, have invented certain new and ous gas has been compressed to apressure suflicient to prevent the constituent elements of thesubstances under treatment from becoming vaporized at the temperaturethat is employed.

The accompanying drawing illustrates by way of example in verticalsection a. constructional form of an apparatus for carrying the improvedroasting process into effect, as applied to coffee.

As shown, the improved apparatus comprises a charging hopper 1; areceiver 2 capable of communicating with the hopper by means of a sluicevalve 3; a roasting chamber 4: capable of communicating with thereceiver 2 by means of a sluice valve 5; a cooling chamber 6 capable ofcommunicating with the roasting chamber by means of a sluice valve 7 adischarging pipe 8 and a box 9 that canbe placed alternately incornmunication with the cooling chamber by means of a three-way cock 10;an endless conveyor 11 for receiving the materials falling through theipe 8; a tank 12 containing water in the ottom of whichis a perforatedpipe 13 communicating by means of a pipe 14: with the box 9, and a pipe15 which communicates with a supply of compressed air and which bymeansof cocks 16 and 32, allow of passing compressed air into thevroastingchamber 4 and the cooling chamber 6.

The charging hopper 1 having been filled with, for instance, raw cofiee,the-valve 3 is opened, the valve 5 being ke t shut; the codee will rundown into an fill the receiver2. The valve 3 is then closed, and thevalve 5 opened, so that all the cofiee contained in the receiver 2 willfall into the roasting chamber 4. The latter which is of circular shapeand of comparatively small height, contains in its upper part anarrangement of electric heaters, only one element 17 of which is shown.

The current is supplied to these heaters by means of a device thatallows of varying their intensity, and consequently of regulating thetemperature inside the roasting chamber 4.

Through the central part of the lowerplate or bottom of the roastingchamber 4, there extends, guided in a packing box, a vertical shaft 18provided with two horizontal arms, one of which carries an inclined rakeorv scraper 19, and the other a series of shares 20. On that part of theshaft 18 situated below the roasting chamber, there is fixed a levelpinion 21 gearing with a driving wheel 22. As they revolve, the rake andthe shares stir up the coffee in "the roasting chamber.

The bottom of the roasting chamber 4:

comprises an inclined portion formed as a hopper or spout 4* above thevalve 7. The

upper orifice of this-spout is closed during the roasting operation by atrap door 23 which can be lowered by means of a lever 24 withantifriction roller, actuated from the outside by means of'a handle 25.

The top of the roasting chamber is fitted with a pressure gage 26, athermometer 27, and a safety valve 28.

At each operation air is admitted into the roasting chamber, at apressure such that when it is heated to a temperature of about 175degrees centigrade, it will have attained a pressure of about 15atmospheres. Then, the cofi ee is charged into the roasting chamber ashereinbefore described. The electric current is'turned on so as to raisethe temperatureto 175 degrees C., and the coffee is stirred by rotatingthe rake 19 and the shares 20 so as to assure its becoming uniformlyroasted.

The pressure produced the roasting When the roasting operation iscompleted, the valve"? is opened to place the roasting chamberintocommunication with the cooling chamber 6.

This chamber 6 is somewhat similar to the roasting chamber, except thatit has no radiator; that the shaft 18 enters it from the top and that ithas a double bottom 29 formed by 'a perforated'metal plate upon whichthe roasted coflee is stirred.

The bottom of thisi'cooling chamber has also an inclined part formed asa hopper 6". The perforated plate 29 has a radial opening 29 situatedover this hopper, which can be shut by means of a register 30 operatedfromthe outside by means of a handle 31.

The same pressure as in the roasting chamber has been previouslyestablished in the cooling chamber'by opening the cock 32. Thereforewhen the coflz'ee discharged from vthe roasting chamber passes into thecooling chamber it will be under the same pressure while it is beingwell' stirred. The temperature drops quickly, andafter a 'few moments,the cock 10 is opened gradually to establish communication with the box9.

- The pressure then falls rapidly, and the expansion of the air producesa considerable and rapid drop in temperature.

It is, however, to be understood that during this entire coolingoperation, the temperature drops more quickly than the pressure,stituents of the coffee volatilize.

- The expansion of the air causes all the skins of'the cofl'ee beans torun together. The said skins are arrested by baflies 33 arranged in thebox 9 and accumulate in the bottom part of this box while the air thatescapes through the pipes 14, 13, bubbles up through the water 111 thetank 12.

When the interior of the cooling chamber has the same pressure as thatobtaining outside the same, the cock 10. is operated to place thecooling chamber in communication with the outlet pipe 8. The handle 31is actuated so as to allow the coffee to fall on to the conveyer 11which conveys it for instance to a warehouse for storing or pack- 1nlfhe receiver, the roasting chamber and the cooling chamber operate allat the same time and under the same pressure, so that the roastingprocess is practically continuous.

The improved apparatus may also be employed for roasting cocoa beans,etc.

What I claim is 1. A process for roastmg coifee, which so that at-notime can the volatile conconsists in subjecting the coffee to a heatingand to a cooling operation and keeping the coifee during the heating andcooling operation in an atmosphere of compressed air or other innocuousgas under a pressure tliat 1s hlgher than the max1mum tenslon of thevapors that can be given oh by the said coffee at its roastingtemperature.

- 2. An apparatus for roasting coffee other substances, comprlsingvessels of suitadapted to be placed in communication by means of a trapdoor and a sluice valve with the lower vessel that serves to cool theroasted substance. 7

3. A process for the roasting of coffee and other substances consistingin subjecting the substance to heat in a compressed atmosphere innocuousto the substance, and under pressure above the vapor tension of theconstituents of the substance caused by the heat, stirring the substancewhile it is so heated, and then cooling the substance while it isstirred by a rapid reduction of temperature and pressure at a rate suchthat the pressure is always above the vapor tension of the constituentsof the substance caused by the heat.

4. A process for the roasting of coffee, consisting in subjecting thecofiee to heat at a temperature of substantially 175 in an inoffensiveatmosphere which is under a. pressure of about 15 atmospheres, stirringthe coffee while it is so heated, then cooling the coffee while it isstirred and reducing the pressure at a rate such that the pressure isalways above the vapor tension of the constituents of the cofiee causedby the heat during its reduction.

5. An apparatus for roasting coffee and other substances, comprising aroasting chamber, a cooling chamber, means for supplying air underpressure independently to said chambers, stirring means associated withsaid chambers, and means for reducing the pressure in the coolingchamber at a rate such that the pressure is always above the vaportension of the constituents of the substances caused by the reduction ofheat.

In testimony whereof I have hereunto set my hand at Paris, (France),this 25th day of May 1915.

PIERRE MALVEZIN.

